1. Field of the Invention
The present invention relates to a reel for holding binding wire. The reel with the binding wire is mounted to a binding tool which is used to bind objects of interest. Specifically, the wire contained on the reel is fed to the binding tool which cuts and twists the wire around architectural reinforcing bars.
2. Description of the Related Art
In reels of this type, the connection of the terminal end of the wire held on the reel is used to control the rotation of the reel. Thus, if the terminal end of the wire held on the reel is not directly connected to the reel, the reel cannot be rotated, In this method, the ability of the reel to rotate is used to determine whether or not all the wire on the reel has been used in the binding operations. Thus, when the reel can no longer be rotated, the wire supply on the reel has been exhausted. When the wire supply has been exhausted, the binding process is then brought to a stop.
In order to simplify the process for determining when the supply of wire has been exhausted and for bringing the binding operation to a stop, an optical sensor system may be used. Reflected light through a detection mark formed on the side surface of the reel may be detected by an optical sensor. The optical sensor system consists of a light emitting element and a light receiving element respectively disposed opposite each other in the reel support portion of the binding tool.
However, because tools such as a binding tool and the like are used in a variety of lighting conditions, detection errors with the optical sensor system caused by the differences in the light intensities in different environments cannot be avoided. For example, differences in light intensities between the outdoors and various lighting conditions indoors frequently result in erroneous readings in the optical sensor system attached to such binding tools. Such erroneous readings can interfere with the operation of the binding tool and thereby prevent the stable operation of the binding process.